Hi Neoflash,

which text book are you referring to? Which chapter?

Because I think you are confusing different issues. I guess what you mean are idle tones, which might
be a problem in single-bit low-order (1st&2nd order) modulator.
Please post the full reference of the text book to clarify the question.

Regards

Hi,

the name of the book is "UNDERSTANDING delta-sigma data converters". I think the difference is that in fig 3.6 the spectrum is shown using averaging
(uncorrelated noise is reduced and the tones are better visible), while in fig. 2.20 no averaging is used and it is therefore hard to distiguish
between noise and tones.

But in general a first-order modulator is worse than second-order in terms of tonal behavior.

Regards